Method and means for making laminated glass



May 6, 1933- A. G. WORRALL METHOD AND MEANS FOR MAKING LAMINATED GLASS Filed Aug. 17, 1928 Glass Celluloid.

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PatentedMay 16,1933 Q I a 1,909,444

' UNITED STATES PATENT! OFFICE ARTHUR G. WOBBALL, OI PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO LOUIS I.

KOLB, OF PHILADELPHIA, PENNSYLVANIA, TRADING AS SAFETEE GLASS COM- PANY mm'rnon AND MEANS FOR MAKING LAMINATED ems's Application filed August 17, 1928. Serial No. 300,173.

My invention has for its object a commerform closelythereto so that said surfaces are cially eflicient method. and means for the 1n perfect contact and leave no spaces or id manufacture f l i t d gla s, crevices for the subsequent entrance of air. More particularly, my invention is intend- The compressed air is preferably applied for 5 ed to provide a simple and inexpensive form approximately three to five minutes and is of apparatus adapted for carrying out the then shut off and the pot vented to remove process for thoroughly uniting the layers of the pressure. Thereupon, a cooling fluid, glass to the interposed sheet of celluloid or preferably Water, is admitted to the pot and pyjroxylin material, insuring the removal of about the vacuum bag and its contents to cool 10 all air, vapors and moistures which may the same with reasonable rapidity to permit have been present between the several layers the pot to be opened and the contents reof the sandwich; and further, to also 111- moved without inconvenience. Air is then sure adequate heat and pressure to be applied admitted to the bag or receptacle to remove to cause a thorough welding of the layers to atmospheric pressure from the glass sandeach other without breakage. I wlch, which may then be withdrawn from In utting my improved method into practhe bag 1n 1ts completed form. Thereafter, tice enclose the glass and celluloid sandit 1s only necessar to grind the edges when wich within a flat bag or receptacle of rubrequlred to provi e a finished appearance to ber or other suitable flexible material, and the product. temporarily seal the same against the en- In carrying out the above stated process, trance of air; thereafter exhausting the air, 1t is desirable that certain refinements thereof vapor and moisture from within the bag or be employed, and among these may be menl l tioned that during the application of the vacuum and thereby the flexible walls of the steam pressure to the vacuum bag and its 25 bag to lie in close contact with the outercontents within the pot, it is desirable that surfaces of the glass. The bag with its conthe steam should be adm d n r a otained glass and celluloid sandwich is then matlc control at a pressure of 15 lbs. with placed within a closed pot or chamber can an approximate temperature of 250 degrees pable of withstanding considerable pressure, F., while at the same time the outlet for and the lid or cover thereof having been firmwater of condensation and air is also autoly secured in place, steam at a pressu e of matlcally controlled to maintain a back presapproximately fifteen pounds (having a temsure of approximately 10 lbs. at the outlet, rature of .250 degrees F.) is admittedand whereby there is a pressure differential of allowed to bring the bag and its lo d approxlmately 5 lbs. between the inlet and a sandwich to a temperature of 240 degrees outlet of the pot.

F. -or thereabouts, said temperature being By maintaining a pressure differential for maintained for a time sufiicient to enable the the steam between the inlet and outlet of red a definite circulacelluloid or binder material between the glass the pot, there is insu sheets, to become pliable and more or less tion of steam over and about the vacuum bag lastic. or enclosure for the sandwich, resulting in Following the above described operation, a rapid, thorough and uniform heating therethe steam supply is shut off and the bag and of and whereas the preferred differential its contents subjected to a pressure of apof 5 lbs. is 30% of the maximum steam pres proximately 160 lbs. by admission of comsure, the temperature differential amounts pressed air to the closed pot or chamber, said to only 10 degrees F. or 2 of the temressure being maintained for a few minutes perature of the initial steam supply, and to complete the. weld. The result of the treat consequently the temperature conditions ment just described is that the celluloid or within the pot are approximately uniform. binder layer is thoroughly compressed be- My invention comprehends other details tween the glass surfaces and made to conin method and apparatus which, together abouts, which after described.

with those above referred to, are fully described hereinafter and pointed out in the claims.

M improvements will be better understood by reference to the drawing, in which: Fig. 1 .is a diagrammatic elevati n of an apparatus having a construction suitable for the carrying out of my improved process; Fig. 2 is a transverse vertical sectional view through the lower part of the pot structure enclosing the vacuum bags in position therein; Fig. 3 is a longitudinal vertical sectional view of one of the vacuum bags, charged with the sandwich and positioned upon its support ready for insertion in the pot; Fig. 4 IS a diagram illustrating a side view of means for inserting the sandwich into the bag; 5 is a vertical sectional view of a modifie construction of bag support within the pot; and Figs. 6 and 7 are edge views of two forms of laminated lass to be made by my improved method an means.

2 illustrates a strong pot or chamber having a closure or lid 3 preferably arranged at the top and adapted to be secured to the pot by suitable clamping bolts 4. This cover or lid may be raised or lowered by suitable hoisting means 5 whereby it may be removed when insertin or withdrawing the contents to and from t e pot. I do not restrict myself to any particular size or construction of the pot beyond the fact that it should be of suflicient strength to resist bursting under pressure of 160 lbs. per square inch or therepressure is applied as herein- A steam supply pipe 6, havin communication with the upper portion 0 the Pet 2, ma' receive steam from any suitable source suc as main 7, which steam may be admitted or shut off by a valve 9. The pipe 6 is provided with a pressure reducing valve 8 of any usual construction which is so positioned and adjusted that it will maintain on its delivery side and in the pot a steam pressure of approximately 15 lbs. per square inch. It will not be necessary to describe any particular form of the pressure reducing valve 8 inasmuch as .valves of this character are well known in the commercial market. A shut-off valve 12 may be arranged upon the pipe 6 and close to the pot, so as to avoid any undue pressure upon the pressure reducing valve 8 when the pot is later subjected to the h' her pressure previously referred to.

e lower part of the 2 is provided with an exhaust or discharge pipe 10 for water of condensation, air and steam, preferably caused to pass through the automatic pressure relief'valve 11 arranged in said pipe and adjusted to permit the escape of steam (as well as water and air) when the outlet pressure exceeds IO-lbs. (corresponding toa temperature of240 degrees F.), or at any other ressure less than the initial steam pressure elivthrough the ered to the pot, as may be preferred, the same being assured by proper adjustment of the automatic relief valve. A hand valve 13 may be arranged in the pipe 10 between the automatic valve 11 and the pot, whereby the higher pressure later to be delivered to the pot may be prevented from acting upon the mechanism of the pressure controlling valve 11. is a drain pipe which may communicate with the pipe 10 between its valve 13 and the pot and is controlled by a-valve 21.

14 is a compressed air pipe and is connected into the upper part of the 0t 2 and communicates with a source or tan of compr ssed air 14a having a pressure of approximately 160 lbs. to the square inch, the said source being maintained by air compressor 14?) and a relief valve 140. The compressed air. flowing said pipe 14 to the pot may be controlled by a valve 15. Opening upward from the pipe 14 is a vent pipe 16 which is provided with a valve 17. In addition to the vent pipe, a cold water pipe 18 may also be connected with the pipe 14 betweenits valve 15 and the pot, and said water pipe 18 is provided with a control valve 19. In this man.- ner, compressed air may be supplied to'the pot or vented therefrom. 7 Similarly, water may be supplied to the pot and subsequently drained therefrom by the drain pipe 20.

Referring now to the vacuum bag construction constituting the receptacle or enclosure in which the glass and celluloid sandwich is placed during the treatment: 23 is :1 rectangular supporting frame or tray providing a supporting surface and side channel frames 22 and also having at one end a suitable clamping means 24. 25 is a rectangular bag preferably having a greater length than width and composed of a rubber and textile fabric for flexibility, lightness and strength and having one end open as at 26. Extending from the bag near-the open end is an exhaust tube 27 through which the-air and vapor contents of the bag may be exhausted and the tube subsequently plugged, as indicated at in Fig. 3.

i 28 represents the sandwich of glass and celluloid in position within the bag, andv 29 are templets or non-compressible strips arranged about the perimeter of the sandwichto prevent excessive pressure coming upon the edges of the glass. For conveniently inserting the sandwich or, sandwiches into the bag, I proceed as follows: Upon a thin steel plate 23a (Fig. 4) of approximately the full width of the interior of the bag, I spread a long strip of light canvas 25a and uponthis and above the plate, I arrange the or sandwiches and templets, and then fold the remaining portion of the canvas over the sandwich and templets abovethe plate, as indicated in dotted lines in Fig. 4. The plate 230. with its load is then inserted through the mouth 26 of the bag 25 and moved backward sandwich .tity of work to be done.

therein until the parts are entirel within the bag and at some distance from t 'e open end thereof. Without disturbing the sandwich or templets, I next gently withdraw the thln steel plate 23a alone, thereby leaving the sandwich structures, templets, and enclosing canvas in proper position withln the bag.

While I have shown within the bag one laminated plate of relatively large size, 1t will be understood that the areas of these may vary according to the requirements of the artici-e, som times being rectangular or circular and otherwise shaped according to its subsequent or intended use. The bag may, therefore, be practically filled wlth sandwich sets of glass and celluloid, according to its capacity and the relative sizes of the" articles.

After being loaded with the sandwich.

structures, the end layers 26 of the open end of the bag are placed between clamping plate 24a and the plate 240 of the clamp 24 (h1nged to the table frame at 24d), and sald plates 24a and 240 are respectively pressed tightly upon the layers of the open end of the bag as shown at 26, by means of clamping screws 24?), so as to hermetically seal the entrance to the bag. When this is accomplished and the plug 30 removed, the nipple 32 of vacuum tube 31 is inserted in place of the plug'and thereafter the valve 33 is opened and the vacuum existing in pipe 3&1 acts to withdraw all of the air, vapor, moisture or other volatile substances from the ba the plates of the sandwich; and aside from exhausting the air, vapor and moisture from the bag, the vacuum also causes the flexible top and bottom layers of the be to press tightly upon the outer surfaces 0 the glass sheets for holding them firmly upon the intermediate celluloid or hinder layer of the sandwich. When the bag has been thoroughly exhausted, the nipple 32 may be withdrawn from exhaust tube 27 of the bag, and the within the pot immediately above the frame and bag first inserted, and similarly, any number of additionalframes and bags with their contents may be stacked one above the other, according to the re uirements or quan- .ssumin that the pothas been fully charged, it will he noted that the bags and table frames supporting them do not extend to the sides or ends of the pot, but are open on all sides, top and bottom, so as to permit free access of the steam, air and water to be employed in'carrying on the process. If the bags are made in width and from between 7 however,

of said table may rest directly upon the side portions of the bag, as shown in Fig. 2. I, however, do not limit myself in this respect, as the bags may be of less width than the distance apart of the longitudinal side portions of the frame 22, so as to extend between said portions but without having them rest directly upon the bag, as indicated in Fig. 5. After the pot is fully charged, the lid or cover 3 is lowered and tightly clamped into position. V

. To facilitate the circulation of the steam in the heating of the bag enclosure 25, the tray or table plate 23 and the side frames 22 may be peforated to constitute open-work, as mdicated in Fig. 5, but I do not restrict myself in this respect.

When the pot is sealed, the valves 9, 12and 13 are opened, and thereupon steam will enter the pot at its upper part under a pressure of approximately 15 lbs. and at a temperature of 250 degrees F. The supply of steam is continued for' approximately twenty minutes. During this time, the water of condensation, air and some steam is permitted to flow out through pipe 10 and control relief valve 11. The latter permits the escape of steam that may exist at the outlet at a pressure below 15 lbs. and a temperature of ap roximately 240 degrees F. In this way, t e steam is caused to circulate through the pot and-reach the bags from all sides so thatthe contents thereof are subjected to a temperature of between 240 and 250 degrees F. If no steam was allowed to circulate through the discharge pipe 10, the entrance of live steam into the pot at the inlet would be restricted to a rate commensurate to the condensation only and would, under those conditions, be very slow in heating the contents in the pot and moreover, would cause relatively under-heat ing for the contents of the lower bags as compared to that of the upper bags. When, however, the steam is permitted to circulate entirely through the pot, and pass into the escape pipelO at a pressure and temperature somewhat less than that of the steam entering at the 'top of the pot, the heating is -positive,

more uniform, and greatly more rapid, with the result that the time required in racticing the process is shortened and therehy insures. greater capacity, to the apparatus:

WhileI have stated that it is desirable to subject the loaded bags to a temperature treatment for approximately twenty minutes,

to soften the celluloid or pyroxylin, I do not restrict myself in this respect. I have found, however, that in practice this period of time is e'fiective with the average character of materials employed and with the vacuumbags or enclosures of substantial construction.

By reason of the vacuum within the be the walls thereof are held in contact wlth the glass surfaces very closel and under a pressure approximate y equa to or greater than 15'lbs. per square inch (partly due to the initial pressure of the live steam admitted to the pot), and consequently the conduction of the heat from the live steam through the bag and glass to the celluloid or binder of the sandwich is effective and rapid in action.

When the proper heating has been accomplished, it is necessary to apply a much greater pressure than that provided by steam, for insuring the proper shaping of the celluloid or pyroxylin between the glass plates, all of WlllCll must be done before the sandwich cools. The desired result is speedily obtained by closing the steam valves 12 and 13 and 0 ning valve 15; whereupon compressed air, 0 approximately 160 lbs. per square inch, is admitted to the pot, causing a pressure of this character to be applied to the vacuum bags and their contents for the short period of about three minutes, previously indicated as suflicient in practice, though a longer period may be employed, if so desired.

Immediately following the application of pressure by the compressed air, the valve 15 is closed, the valve 17 is opened to vent the pot and cold water is admitted by pipe 18 under control of the valve 19, thereby filling the pot and surrounding vacuum bags therein for the purpose of chilling the laminated glass sandwich and setting the celluloid or pyroxylin binder. After the pot is filled -with water and the cooling accomplished,

valve 19 is closed and valve 21 opened, whereupon the water within the pot may drain off tothe sewer. The lid of the pot may then be lifted and the contents of the pot removed. The table frames with their associated vacuum bags are then placed upon a convenient table, clamps 24 released and contents of the bags withdrawn, the opening of the bags acting to break the vacuum by permitting air to enter.

The breaking of the vacuum within the bags maybe done before'opening of the same, by withdrawing the plugs 30. Each bag may then be opened by releaslng the clamps 24 and throwing them back from the rubber bag and about their pivotal connections 24d. Thereafter, the completed laminated glass and templets may be withdrawn by pulling upon the ends of the canvas sheet 25a.

In this application I do .not claim the specific form of the tray or vacuo-enclosure, nor features directly associated with them, as they form subject matter of a copending application Serial No. 315,977, filed October 30, 1928.

I have described my improved method and means in that particularity which I deem to be the best exposition of my invention and that which I prefer in commercial practice,

but I do not restrict or confine myself to the minor or secondary details, as such are susceptible of modification, which may be resorted to as matters of mechanical skill and without a departure from the spirit of the invention.

Having now described my invention, what I claim and desire to secure by Letters Patent is: i

1. The herein described method for the manufacture oflaminated glass, which consists in assembling a sandwich formed of two sheets of glass with an interposed binder capable of being softened by heat and placing the same within an enclosure having flexible walls and forming a partial vacuum within the structure whereby air, vapor and moisture are remot ed from the sandwich; confining the said enclosure and its contents within a closed chamber while subjecting them therein to steam having a sufficiently high temperature to soften the binder and maintaining the sandwich in said heated condition and under the direct pressure of the steam until the binder thereof is softened; thereafter subjecting the chamber and enclosure containing the heated sandwich to the action of a fluid medium having a pressure suflicient to compress and shape the softened binder material of the sandwich closely to the opposing surfaces of the glass sheets thereof; cooling the enclosure and sandwich therein; and finally removing the completed sandwich from the influence of the vacuum into the normal atmosphere for use as laminated glass; and wherein further, the pressure supplied to the chamber and upon the enclosure containing the sandwich is obtained by means of compressed air admitted to chamber.

2. The herein described method for the manufacture of laminated glass, which consists in assembling a sandwich formed of two sheets of glass with an interposed binder capable of being softened by heat and placing the same within an enclosure having flex-' ible walls and forming a partial vacuum within the structure whereby air, vapor and moisture are removed from the sandwich; confining the said enclosure and its contents within a closed chamber while subjecting them therein to steam having a sufficiently high temperature to soften the binder and maintaining the sandwich in said heated condition and under the direct pressure of the steam until the binder thereof is softened; thereafter subjecting the chamber and enclosure containing the heated sandwich to the action of a fluid medium having a pressure sufiicient to compress and shape the softened binder material of the sandwich closely to the opposing surfaces of the glass sheets thereof; cooling the enclosure and sandwich therein; and finally removing the completed sandwich from the influence of the vacuum into the normal atmospherecool gaseous fluid having a pressure of approxnnately 160 pounds per square inch.

nated glass, which consists of asteam tight chamber; a vacuo-enclosure having flexible walls in which the sandwich of which the H laminated glass is to be made is placed. said enclosure having a temporarily sealed opening through which the air may be exhausted to provide a Vacuum within the enclosure and also having a larger opening through which the enclosure may be charged with the sandwich; a supporting tray upon which the enclosure rests in a horizontal position and having clamping means for sealing the charging opening of the vacuo-enclosure, said tray of a size to be received within the steam tight chamber; means for directly suplying steam at a temperature sufficiently high to allow a proper union of the parts composing the sandwich and permitting the escape of the water of condensation;

means for admitting a fluid medium to thechamber under a pressure suflicient and in excess of the steam pressure to compress the materials of the sandwich to form an air tight union between them; and means for cooling the chamber and the enclosure arranged therein containing the sandwich, whereby the sandwich may become highly heated and compressed while in a vacuo and thereafter may be removed for use under ordinary atmospheric conditions; and wherein further, the means for admitting the fluid medium for compressing the materials constituting the sandwic comprises devices for compressing air and controllably delivering it into the chamber.

4. Means for the manufacture of laminated glass, which consists of a steam tight chamber; a vacuo enclosure having flexible walls in which the sandwich of which the laminated glass is to be made is placed, said enclosure having a temporarily sealed opening through which the air may be exhausted to provide a vacuum within the enclosure and also having a larger opening through which the enclosure may be charged with the sandwich; a supporting tray upon which the enclosure rests in a horizontal position and having clamping means for sealing the charging opening of the vacuo-enclosure, said tray of a size to be received Within the steam tight chamber; means for directly supplying steam at a temperature sufliciently high to allow a proper union of the parts composing the sandwich and permitting the escape of the Water of condensation;

means for admitting a fluid medium to the chamber under a pressure sufiicient and in excessof-the steam pressure to compress the materials, of the sandwich to form an air tightl union between them; and means for cooling the chamber and the enclosure arranged therein containing the sandwich,

whereby the sandwich may become highly heatedand compressed while in a vacuo and 3. Means for the manufacture of lami- "thereafter may be removed for use under ordinary atmospheric conditions; and where- .in further,'the vacuo-enclosure is also provided with charging and discharging means comprising a thin metallic plate of a length and width substantially corresponding to that of the enclosure, and a continuous flexible sheet of approximately twice the length also having a larger opening through whichthe enclosure may be charged with the sandwich; a supporting tray upon which the enclosure rests in a horizontal position and having clamping means for sealing the charging opening of the vacuo-enclosure, said tray of a size t be received within the steam tight chamber; means for directly sup lying steam at a temperaturesufiiciently big to allow a proper union of the parts composing the sandwich and permitting the escape of the water of condensation; means for admitting a fluid medium to the chamber under a pressure sufiicient and in excess of the steam pressure to compress the materials of the sandwich to form an air tight union between them; and means for cooling the chamber and the enclosure arranged therein containing the sandwich, whereby the sandwich may become highly heated and compressed while in a vacuo and thereafter may be removed for use under ordinary atmospheric conditions; and wherein further, a series of vacuo-enclosures are supported. one above the other in separated relation by the supporting trays within the chamber and said trays rovided with longitudinal side frames exten ing downwardly and resting upon the side portions of the respective vacuo-enclosures, the latter being formed of flat rubber top and bottom layers connected at their side edges in closely folded flat side portions.

6. In apparatus for producing laminated glass, which consists of a steam tight chamthe steam to escape from the chamber at a substantially constant temperature lower than that of the steam supply, means for supplying compressed air at high pressure to the chamber, means for supplying cooling water to the chamber, and valves for controlling the supply and escape of steam and also the individual supply of compressed air and water, combined with a vacuo-enclosure formed of flexible material and supported within the chamber said enclosure provided with clamping means for hermetically sealing it during treatment Within the chamber In testimony of which invention, I hereunto set my hand.

. ARTHUR G. WORRALL. 

